Pillow/PIL/TgaImagePlugin.py

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#
# The Python Imaging Library.
# $Id$
#
# TGA file handling
#
# History:
# 95-09-01 fl created (reads 24-bit files only)
# 97-01-04 fl support more TGA versions, including compressed images
# 98-07-04 fl fixed orientation and alpha layer bugs
# 98-09-11 fl fixed orientation for runlength decoder
#
# Copyright (c) Secret Labs AB 1997-98.
# Copyright (c) Fredrik Lundh 1995-97.
#
# See the README file for information on usage and redistribution.
#
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from PIL import Image, ImageFile, ImagePalette, _binary
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__version__ = "0.3"
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#
# --------------------------------------------------------------------
# Read RGA file
i8 = _binary.i8
i16 = _binary.i16le
i32 = _binary.i32le
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MODES = {
# map imagetype/depth to rawmode
(1, 8): "P",
(3, 1): "1",
(3, 8): "L",
(2, 16): "BGR;5",
(2, 24): "BGR",
(2, 32): "BGRA",
}
##
# Image plugin for Targa files.
class TgaImageFile(ImageFile.ImageFile):
format = "TGA"
format_description = "Targa"
def _open(self):
# process header
s = self.fp.read(18)
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idlen = i8(s[0])
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colormaptype = i8(s[1])
imagetype = i8(s[2])
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depth = i8(s[16])
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flags = i8(s[17])
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self.size = i16(s[12:]), i16(s[14:])
# validate header fields
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if colormaptype not in (0, 1) or\
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self.size[0] <= 0 or self.size[1] <= 0 or\
depth not in (1, 8, 16, 24, 32):
raise SyntaxError("not a TGA file")
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# image mode
if imagetype in (3, 11):
self.mode = "L"
if depth == 1:
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self.mode = "1" # ???
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elif imagetype in (1, 9):
self.mode = "P"
elif imagetype in (2, 10):
self.mode = "RGB"
if depth == 32:
self.mode = "RGBA"
else:
raise SyntaxError("unknown TGA mode")
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# orientation
orientation = flags & 0x30
if orientation == 0x20:
orientation = 1
elif not orientation:
orientation = -1
else:
raise SyntaxError("unknown TGA orientation")
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self.info["orientation"] = orientation
if imagetype & 8:
self.info["compression"] = "tga_rle"
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if idlen:
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self.info["id_section"] = self.fp.read(idlen)
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if colormaptype:
# read palette
start, size, mapdepth = i16(s[3:]), i16(s[5:]), i16(s[7:])
if mapdepth == 16:
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self.palette = ImagePalette.raw(
"BGR;16", b"\0"*2*start + self.fp.read(2*size))
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elif mapdepth == 24:
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self.palette = ImagePalette.raw(
"BGR", b"\0"*3*start + self.fp.read(3*size))
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elif mapdepth == 32:
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self.palette = ImagePalette.raw(
"BGRA", b"\0"*4*start + self.fp.read(4*size))
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# setup tile descriptor
try:
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rawmode = MODES[(imagetype & 7, depth)]
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if imagetype & 8:
# compressed
self.tile = [("tga_rle", (0, 0)+self.size,
self.fp.tell(), (rawmode, orientation, depth))]
else:
self.tile = [("raw", (0, 0)+self.size,
self.fp.tell(), (rawmode, 0, orientation))]
except KeyError:
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pass # cannot decode
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#
# --------------------------------------------------------------------
# Write TGA file
o8 = _binary.o8
o16 = _binary.o16le
o32 = _binary.o32le
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SAVE = {
"1": ("1", 1, 0, 3),
"L": ("L", 8, 0, 3),
"P": ("P", 8, 1, 1),
"RGB": ("BGR", 24, 0, 2),
"RGBA": ("BGRA", 32, 0, 2),
}
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def _save(im, fp, filename, check=0):
try:
rawmode, bits, colormaptype, imagetype = SAVE[im.mode]
except KeyError:
raise IOError("cannot write mode %s as TGA" % im.mode)
if check:
return check
if colormaptype:
colormapfirst, colormaplength, colormapentry = 0, 256, 24
else:
colormapfirst, colormaplength, colormapentry = 0, 0, 0
if im.mode == "RGBA":
flags = 8
else:
flags = 0
orientation = im.info.get("orientation", -1)
if orientation > 0:
flags = flags | 0x20
fp.write(b"\000" +
o8(colormaptype) +
o8(imagetype) +
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o16(colormapfirst) +
o16(colormaplength) +
o8(colormapentry) +
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o16(0) +
o16(0) +
o16(im.size[0]) +
o16(im.size[1]) +
o8(bits) +
o8(flags))
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if colormaptype:
fp.write(im.im.getpalette("RGB", "BGR"))
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ImageFile._save(
im, fp, [("raw", (0, 0) + im.size, 0, (rawmode, 0, orientation))])
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#
# --------------------------------------------------------------------
# Registry
Image.register_open(TgaImageFile.format, TgaImageFile)
Image.register_save(TgaImageFile.format, _save)
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Image.register_extension(TgaImageFile.format, ".tga")